Skills for Study Level 2 Teacher's Book - Cambridge University Press

2 Analyzing the suitability of samples2a Note: This task is intended to illustrate the problem of self-selection by researchsubjects.Suggested answersThe validity of the study is low. The conclusion that 95% of British people wouldlike to pay to live in an eco-friendly home is based on the fact that 94.8% of thepeople who responded to the survey said ‘yes’. However, 55% of the people towhom the questionnaire was sent never replied. As about 93% of the peopleresponding to the survey indicated that they were interested in environmentalissues, it might be assumed that the people who did not bother to reply to thesurvey did not hold the same views.2b Students check their ideas with a partner.2c This task is intended to make students more aware of issues with random samples.2d Students compare their ideas with a partner.2e & 2f Student discussion2gSuggested answersThe sample will include only Chinese students studying in the UK. No oneactually living in China at the time will be sampled. This will lower the validity ofthe study somewhat, as large sections of the Chinese population will be missingfrom the sample (e.g. demographic status, age, etc.). Also, as it is based onChinese people living outside China, it is possible that their attitudes will notreflect mainstream opinions among Chinese who have remained in China.2hSuggested answersStudy 1The sample seems reasonable, as it gives a cross-section of different ages andfamily types, with and without children.Study 2There are issues with the sample. It is intended to study back pain, though mostof the volunteers have never reported any episodes of back pain before, so itcannot be concluded that their absence of back pain is due to the new chairdesign.2i Students check their ideas with a partner.2jAnswersThe author claims that in ‘Asia’ and ‘the West’ there are different seatingpreferences. Though experience might tell many people that this may betrue, the evidence here does not support the conclusion, as it studied onlySingaporeans and American university students; therefore other populationgroups are not considered, and it is assumed that the situation in Singapore orAmerica holds good in other areas of Asia and the West respectively.Unit 4 Part C ∙ Investigating 122